Ensuring Safety with Theatrical Fog and Haze: Best Practices for Productions

Artificial fog and haze are indispensable elements in theatrical and cinematic productions, creating atmosphere, enhancing lighting, and adding depth to visual storytelling. However, while these effects contribute significantly to the overall impact of a production, they also come with health and safety risks that need to be carefully managed. This blog post explores the mechanisms of fog and haze production, the chemicals involved, potential health impacts, and essential safety guidelines to ensure a safe environment for performers, crew, and audiences.

How Fog and Haze Are Produced

Fog and haze effects are generated by machines that aerosolize a liquid solution into fine particles. These particles are dispersed into the air, creating a visible mist (fog) or a more subtle, light-enhancing atmosphere (haze). The process typically involves heating a fluid—usually water-based and containing glycols, glycerin, or mineral oils—until it vaporizes. As the vapor cools, it condenses into the fine particles that create the desired effect.

Different fluids produce varying particle sizes, influencing the density and duration of the fog or haze. For instance, glycol-based fluids are often used for denser, longer-lasting fog, while mineral oil-based fluids are preferred for finer haze that enhances lighting without being overly visible (Ramboll, 2023).

The Chemicals Involved

The primary chemicals used in fog and haze fluids are dihydric and trihydric alcohols, such as propylene glycol, diethylene glycol, triethylene glycol, and glycerin. These chemicals are selected for their ability to vaporize at relatively low temperatures and their stability in producing consistent effects.

However, even these “safer” chemicals must be used cautiously. Overheating can lead to the decomposition of these substances into potentially harmful byproducts like formaldehyde and acrolein. Standards such as ANSI E1.5-2009 (R2014) specify that these byproducts must remain below permissible exposure limits (PELs) to ensure safety (ANSI E1.5-2009, 2014).

Health Impacts of Fog and Haze

Short-term exposure to theatrical fog and haze is generally considered safe for most people. However, there are potential health impacts, especially for individuals with pre-existing respiratory conditions. Common reactions include irritation of the eyes, throat, and respiratory system. These effects can vary, with some individuals experiencing no symptoms and others having more severe reactions (Aura Health and Safety Corporation, 2018).

Prolonged or repeated exposure, particularly in poorly ventilated spaces or at high concentrations, can exacerbate these symptoms and lead to more serious respiratory issues. Continuous monitoring and limiting exposure time are crucial to minimizing these risks (Colden-Phylmar, 2018).

Essential Safety Guidelines

To mitigate the risks associated with fog and haze, several safety guidelines and best practices should be followed:

1. Limiting Exposure:
Control the duration and intensity of exposure by ensuring proper ventilation, which helps disperse the fog or haze evenly. Providing regular breaks for performers and crew also reduces overall exposure (Safety Bulletin #10, 2019).

2. Monitoring Air Quality:
Use calibrated aerosol monitors, such as the Thermo Scientific PDR-1000AN, to measure particle concentrations in the air. Ensure the calibration factors specific to the machine-fluid combination used are applied for accurate readings (Ramboll, 2023).

3. Qualified Technicians:
Only qualified technicians should operate fog and haze machines. They must follow the manufacturer’s guidelines to prevent the generation of harmful byproducts (Safety Bulletin #10 Addendum A, 2019).

4. Communication and Training:
Ensure all personnel are informed about the use of fog and haze, the potential risks, and the safety measures in place. Safety meetings should be held before rehearsals or performances to review procedures and train staff on minimizing exposure (Safety Bulletin #10, 2019).

5. Special Considerations:
Special care should be taken for individuals who may be more sensitive to fog and haze, such as children, the elderly, or those with respiratory conditions. Minimizing their exposure or finding alternative solutions can help prevent health issues (Aura Health and Safety Corporation, 2018).

Conclusion

While fog and haze are powerful tools for enhancing the visual impact of theatrical productions, their use must be managed carefully to ensure safety. Understanding how these effects are produced, the chemicals involved, and the potential health impacts, combined with adherence to established safety guidelines, allows for the creation of stunning effects without compromising the well-being of performers, crew, and audiences.

References

• ANSI E1.5-2009 (R2014). (2014). Theatrical fog made with aqueous solutions of di- and trihydric alcohols. PLASA North America.
• Aura Health and Safety Corporation. (2018). Health impact assessment of theatrical fog and haze exposure.
• Colden-Phylmar. (2018). Theatrical fog review final report for CSATF.
• Ramboll. (2023). Theatrical smoke, fog, and haze testing: Calibration factors.
• Safety Bulletin #10. (2019). Guidelines regarding the use of artificially created atmospheric fog and haze. Industry-Wide Labor-Management Safety Committee.
• Safety Bulletin #10 Addendum A. (2019). Atmospheric fog & haze – Technical awareness sheet. Industry-Wide Labor-Management Safety Committee.